I find that the MS character heads aren't circles like you've drawn, but are more like rounded rectangles? I think you've also drawn the hands and fingers too slender, while in MS art, they're more round and cartoony.
Very cute! I like the pose you used and the ribbon
Tips I have for you is to use a tool that has blending mode to cell-shade because of the fact that MapleStory's official art has very subtle gradients and airbrush. If you are using SAI, the marker or brush tool would be a good example. They also implement a lot of reflective light (google it if you don't know) in their art. For the shading on the hair, it should be more sharp, contrary to your round shadows on the bangs.
Lastly, the right arm (our view) is too big compared to the one on the left.